The removal and installation of manhole covers pose a problem for those who are charged with maintaining the infrastructure of utilities, such as the telephone system, the waterworks, the sewer system, and the like. A manhole cover may represent any one of a wide variety of heavy metallic and/or concrete structures which overlie an opening into an enclosed structure that is usually, but not necessarily, located underground. Manhole covers come in diverse sizes, shapes, and structures. They may be circular or rectangular in shape, and they may be hinged, as in connection with pull-box covers, or not hinged.
The problem connected with their removal and installation stems from their typically great weight, which is often up to 300 lbs. At this weight, a manhole cover is too heavy for a person to handle without help. However, the use of two or more persons to move the cover poses an impractical solution. The two-person solution is inefficient because it requires two persons in many situations where one person would otherwise suffice. In addition, it is unsafe because two person operations are awkward and present a greater chance of muscle strain and other injuries.
Thus, a tool is needed to help a single person manipulate the cover. Such tools have been devised and used in the utility industries. One such tool is a simple hook which allows for engagement with a manhole cover. However, the simple hook is unsatisfactory because it does not afford sufficient leverage. As a result, a person using a simple hook must bear the entire weight of the cover, and this burden risks injury to the person.
Another prior art tool is illustrated in FIG. 1. As shown in FIG. 1, a handle selectively couples to a chain, which in turn couples to a hook. The handle and its coupling to the chain allow the person to use leverage in manipulating a manhole cover. Thus, a person need not bear the entire weight of the cover and a certain type of injury is reduced. However, the tool shown in FIG. 1 poses different and substantial risks to a person using it. For example, the tool's hook has a tendency to twist when it engages a manhole cover and become instantly disengaged therefrom when great forces are being exerted. Persons operating the tool may find themselves flung backward, often in the face of oncoming traffic. In addition, such persons must at the same time dodge an oncoming hook which is flung toward them when it becomes disengaged from the cover.
The tool shown in FIG. 1 poses additional disadvantages. Persons charged with maintaining utility infrastructures often must deal with a wide variety of manhole cover configurations. While the FIG. 1 tool poses unnecessary risks to its operator in connection with any type of manhole cover, those risks increase when the tool is used in connection with types of manhole covers for which it was not designed to operate. It is impractical to carry many manhole cover tools, each one of which is specifically adapted for its own type of manhole cover configuration. Thus, such persons are urged to use the tool in dangerous situations because no better tools are available. Additionally, the FIG. 1 tool attaches its chain to its handle using a relatively small diameter eye bolt located on the side of the handle to keep the various pieces of the tool together. The proper use of the tool requires the chain to be hooked on an S-hook located on the front of the handle. Apparently this proper use is not obvious from viewing the tool. As a result, pulling operations are often performed using the eye bolt rather than the S-hook to transfer forces between the handle and the chain. Such operations cause damage to the tool.